diff --git "a/\346\226\271\346\263\225\345\244\215\344\271\2402/\347\275\227\344\273\225\345\244\251/Demo02.java" "b/\346\226\271\346\263\225\345\244\215\344\271\2402/\347\275\227\344\273\225\345\244\251/Demo02.java"
new file mode 100644
index 0000000000000000000000000000000000000000..d267f10cb8d8e8105f1e9f57361435223b917420
--- /dev/null
+++ "b/\346\226\271\346\263\225\345\244\215\344\271\2402/\347\275\227\344\273\225\345\244\251/Demo02.java"
@@ -0,0 +1,21 @@
+
+public class Demo02 {
+
+	public static void main(String[] args) {
+		int a=10;
+		int b=20;
+		int c;
+		System.out.println("互换前");
+		System.out.print("a="+a);
+		System.out.print("  ");
+		System.out.println("b="+b);
+		 c=a;
+		 a=b;
+		 b=c;
+		 System.out.println("互换后");
+		 System.out.print("a="+a);
+		 System.out.print("  ");
+		 System.out.println("b="+b);
+	}
+
+}
diff --git "a/\346\226\271\346\263\225\345\244\215\344\271\2402/\347\275\227\344\273\225\345\244\251/Demo03.java" "b/\346\226\271\346\263\225\345\244\215\344\271\2402/\347\275\227\344\273\225\345\244\251/Demo03.java"
new file mode 100644
index 0000000000000000000000000000000000000000..190ec0aafe03e901eaeccaeffff06d75a84cf586
--- /dev/null
+++ "b/\346\226\271\346\263\225\345\244\215\344\271\2402/\347\275\227\344\273\225\345\244\251/Demo03.java"
@@ -0,0 +1,30 @@
+
+public class Demo03 {
+	public static void main(String[] args) {
+		int a []=new int[] {19,15,20,82,100,30};
+		
+		System.out.println("原数组");
+		for (int i = 0; i < a.length; i++) {
+			System.out.print(a[i]);
+			System.out.print("  ");
+		}
+		int d[]=c(a);
+		System.out.println();
+		System.out.println("新数组");
+		for (int i = 0; i < d.length; i++) {
+			System.out.print(d[i]);
+			System.out.print("  ");
+		}
+	
+	}
+	public static int[] c(int a[]) {
+		for (int i = 0; i < (a.length)/2; i++) {
+			int b;
+			b=a[i];
+			a[i]=a[a.length-1-i];
+			a[a.length-1-i]=b;
+		}
+		return a;
+	}
+
+}
diff --git "a/\346\226\271\346\263\225\345\244\215\344\271\2402/\347\275\227\344\273\225\345\244\251/Demo04.java" "b/\346\226\271\346\263\225\345\244\215\344\271\2402/\347\275\227\344\273\225\345\244\251/Demo04.java"
new file mode 100644
index 0000000000000000000000000000000000000000..13241b537f2b97638846b879dcbcb23c2ab6a6b5
--- /dev/null
+++ "b/\346\226\271\346\263\225\345\244\215\344\271\2402/\347\275\227\344\273\225\345\244\251/Demo04.java"
@@ -0,0 +1,35 @@
+
+public class Demo04 {
+
+	public static void main(String[] args) {
+		int a[]=new int[] {15,20,80,10,33,90,6};
+		
+		System.out.println("排序前的数组");
+		for (int i = 0; i < a.length; i++) {
+			System.out.print(a[i]);
+			System.out.print(" ");
+		}
+		
+		int b[]=c(a);
+		System.out.println();
+		System.out.println("排序后的数组");
+		for (int i = 0; i < b.length; i++) {
+			System.out.print(b[i]);
+			System.out.print(" ");
+		}
+	}
+public static int[] c(int [] a) {
+	        int num;
+			for (int i = 0; i < a.length-1; i++) {
+			for (int j = 0; j < a.length-1-i; j++) {
+				if (a[j]<a[j+1]) {
+					num=a[j];
+					a[j]=a[j+1];
+					a[j+1]=num;
+				}
+			}
+		}
+			return a;
+		}
+
+}
diff --git "a/\346\226\271\346\263\225\345\244\215\344\271\2402/\347\275\227\344\273\225\345\244\251/demo01.java" "b/\346\226\271\346\263\225\345\244\215\344\271\2402/\347\275\227\344\273\225\345\244\251/demo01.java"
new file mode 100644
index 0000000000000000000000000000000000000000..bfaec1f32749edd590b3f64ff91ee51d2651ce66
--- /dev/null
+++ "b/\346\226\271\346\263\225\345\244\215\344\271\2402/\347\275\227\344\273\225\345\244\251/demo01.java"
@@ -0,0 +1,31 @@
+package da;
+
+import java.util.Random;
+
+public class demo01 {
+    public static void main(String[] args) {
+    	Random ra= new Random(); 
+    	int a[]=new int[7];
+    	for (int i = 0; i < a.length; i++) {
+			a[i]=ra.nextInt(10);
+			System.out.print(a[i]);
+			System.out.print(" ");
+		}
+    	System.out.println();
+    	b(a);
+}
+    public static void  b(int a[]) {
+    	for (int i = 0; i < a.length; i++) {
+				if (i==4) {
+				System.out.print(" ");
+				System.out.print(a[i]);
+			}
+				else {
+					System.out.print(a[i]);
+				}	
+				
+		
+		}
+
+    }
+}